decltype(auto) in function return type does not deduces const types

In following code:

template<typename T>
struct TD;

decltype(auto) getMyConst() {
    const int val = 10;
    return (const int)val; // const int cast is not needed here actually
}

int main()
{
    
    TD<decltype(getMyConst())> type_test;
}

produces error:

main.cpp:41:32: error: implicit instantiation of undefined template 'TD<int>'
TD<decltype(getMyConst())> type_test;

which indicates that deduced type is int, I would expect decltype rules to deduce const int. Why does clang compiler deduce 'int'?